An efficient synthesis of 1α,25-dihydroxyvitamin D LC-biotin.

In recent years the apparent impact of vitamin D deficiency on human health has gained increased awareness. Consequently, the development of appropriate assays to measure the status of medicinally most relevant vitamin D metabolites in human blood, serum or relevant tissue is continuously being improved. Particularly, assaying of 1α,25-dihydroxyvitamin D, in turn considered as the most active metabolite, is mainly indicated in disorders leading to calcaemia or those resulting from an impaired 1α-hydroxylation of 25-hydroxyvitamin D.

Development of efficient chemical syntheses of vitamin D degradation products.

In recent years it has been recognized that vitamin D deficiency is associated with a wide range of diseases, including various types of cancers. Due to the enormous medical importance of vitamin D and its metabolites, their status in blood serum has to be accurately measured. Thus, the metabolites actually used as reference standards and also others of relevant biological activity have to be provided for validation and continuous improvement of appropriate diagnostic devices.

Chemical, biochemical and microbiological properties of a brominated nitrovinylfuran with broad-spectrum antibacterial activity.

A di-bromo substituted nitrovinylfuran with reported broad-spectrum antibacterial activity was found to be a potent inhibitor of MurA, a key enzyme in peptidoglycan biosynthesis. Further characterization of the compound was carried out to assess its reactivity towards thiol nucleophiles, its stability and degradation under aqueous conditions, inhibitory potential at other enzymes, and antibacterial and cytotoxic activity. Our results indicate that the nitrovinylfuran derivative is reactive towards cysteine residues in proteins, as demonstrated by the irreversible inhibition of MurA and bacterial methionine aminopeptidase.

Phenylalanine 90 and 93 are localized within the phenol binding site of human UDP-glucuronosyltransferase 1A10 as determined by photoaffinity labeling, mass spectrometry, and site-directed mutagenesis.

4-Azido-2-hydroxybenzoic acid (4-AzHBA), a novel photoactive benzoic acid derivative, has been synthesized and used as a photoprobe to identify the phenol binding site of UDP-glucuronosyltransferases (UGTs). Analysis of recombinant His-tag UGTs from the 1A family for their ability to glucuronidate p-nitrophenol (pNP) and 4-methylumbelliferone (4-MU) revealed that UGT1A10 shows high activity toward phenols and phenol derivatives. Purified UGT1A10 was photolabeled with 4-AzHBA, digested with trypsin, and analyzed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF)-mass spectrometry.

Synthesis and evaluation of an N-acylated photoactivatable analogue of glutathione as probe for glutathione-utilizing enzymes.

The first synthesis of an N-acylated photoactivatable analogue of reduced glutathione is described. N-(4-Benzoylbenzoyl)glutathione (8) was found to be an inhibitor and a photoaffinity probe of purified rat liver glutathione S-transferases.